I just want more of the game's music to play in more places. There's ton of opportunities to have a song play. Here are some specifics I think would be amazing:
Crashsite - in the mission "Breaking in the Recruits" after the "trapped" party button is activated, and continues to play for the rest of the level, sans the panicked Kora comlink.
Comlink Urgent - for the distress call in the 10-3 mission "A Call to Arms", and in danger mission lobbies.
Boss 2 or Boss 2 danger mission version - during shadow lair boss fights and/or Herex fight.
Blast Network or Barracks - between rooms in the custom mission arenas (eg. rise or fall's final depth).
Main theme - in the final arena before fighting snarbolax and vanaduke. After completing the room the music will not revert - add this behavior to the roarmulus twins final arena as well.
These are the only ones I can think of at the current point in time. Probably are several more, but they're not coming to me.
Any other places music in the game could go where it current isn't?
An excellent suggestion. This kind of thing would really help to show how much the developers care.. In fact, the lack of this sort of attention to detail shows us something else- that we should buy more prize box.